Worksheets18th Edition Mock Paper 9
Total questions: 59
Worksheet time: 30mins
Which standard, for the selection of electrical equipment, cannot be used?
To BS
To BS EN
To IEC
To your own standard
What characteristic of the supply is not required to be included in documentation that should accompany an electrical installation certificate in commercial premises?
The circuits insulation resistance value
The nominal frequency
The nominal voltage
The prospective fault current
In electrical installations, where the protection of safety is paramount the risk of injury may result from?
Ignition of a potentially explosive atmosphere
Non-skilled persons working on electrical equipment
The apprentice leaving live wires exposed
The incorrect equipment being used
BS 7671 is NOT intended to provide safety from electric shock, which may result from?
Interruptions of electrical supply at a travelling fair
Interruptions of supply in an operating theatre
Shock currents on a marina
Unauthorized access to railway signaling equipment
Which of the following voltages between conductors and Earth is defined as low voltage?
35 volts d.c.
600 volts d.c.
650 volts a.c.
950 volts d.c.
A circuit for the transmission of signals intended for control, detection, supervision or measurement of the functional state of a main circuit is known as?
A. A class III circuit
B. A main switching circuit
C. A ring final circuit
D. An auxiliary circuit
The general characteristics of the supply shall be determined by calculation, measurement, enquiry, or inspection. If by enquiry from the distributor how much can the distributor charge? Mark one answer
A. A maximum charge of £50.00
B. A minimum charge of £25.00
C. A sum depending on how much information is required
D. It is free of charge
Which of the following is not an example of an electrical safety service? Mark one answer
CCTV camera systems
Heat extraction equipment
Installations for fire pumps
Smoke extraction equipment
The current carrying conductor composition shown in the diagram below is? Mark one answer
Single-phase 3-wire phase angle 0°
Three-phase 3-wire
Three-phase 4-wire
Two-phase 3-wire
Installations are divide into circuits for a given reason, which option below is not a listed reason? Mark one answer
A. Maintenance
B. Safe Inspection
C. Testing
D. To reduce the current in multiple cables
What earthing system is shown in the image below? Mark one answer
TN-C
TN-C-S
TN-S
TT
Which of the following options is not a check for compatibility of characteristics of equipment used? Mark one answer
Harmonic currents
High frequency oscillations
Maintainability of equipment
Transient overvoltage
To what level of IP protection must the top surface of a barrier or enclosure, that is readily accessible meet?
IP2X
IP4X
IPXXB
IPXXXX
In locations where BE2 conditions exist, measures shall be taken to prevent enclosures of electrical equipment such as a heater under normal operating conditions from exceeding?
60°
70°
80°
90°
Within a domestic premise's switchgear, similar equipment, and consumer units shall be protected against fire caused by electrical equipment by?
Being constructed from heavy gauge plastic
Being constructed from industrial grade polypropylene
Being constructed from insulation material
Being constructed from non-combustible material
A circuit consists of 25 mm² aluminium conductors protected by 60°C thermosetting insulation, the conductors have an initial temperature of 60°C and a final temperature of 200°C, related to the formula below what is the value of k?
A 68
B 93
C 141
D 143
In each part of an installation, at least one protective measure must be used? Which of these is not a recognised protective general requirement? Mark one answer
ADS (Automatic Disconnection of Supply)
FELV
PELV
SELV
Where protection against overload is being considered in chapter 43, disconnection does not necessarily mean?
By manual disconnection
By means of an RCD
Isolation
Through the use of a socket outlet
In an electrical substation supplying a TN system, the power frequency stress voltages, with RE and RB separated, the value of U1 is equal to?
RA x Id
RE·IE + U0
RA + U0 x √3
U0
A circuit protective conductor shall be run to and terminated at each point in the wiring system and at each accessory except?
A A luminaire installed outside a building
B A socket-outlet serving a SELV circuit
C A socket-outlet serving an RCD controlled appliance
D A suspended lamp-holder having no exposed conductive parts
In an a.c. system additional protection by means of a 30 mA RCD shall be provided for socket-outlets providing the maximum rated current of the outlets does not exceed?
16 amps
20 amps
30 amps
32 amps
A commercial fish-breeder has decided to install a reduced low voltage circuit to supply an outdoor pond where the fish stock is kept. What type of source is the installing electrician permitted to install? Mark one answer
A source provided by a TN-C system
A source provided by an IT system
An engine driven generator connected to the public supply
An engine driven generator independent of the public supply
A circuit in an installation has been extended; at the junction box, the cable reduces from 4 mm² to 2.5 mm². Which of these conditions would not require a protective device to provide protection against fault current for the extended circuit? Mark one answer
The cable is for a control cable for a generator
The circuit supplies a measuring device
The extension cable is 2.5 m long
Where disconnection could cause a dangerous condition
What is the minimum impulse withstand voltage for category IV equipment for use in an installation with nominal voltage of 277/480?
1.0 kV
2.0 kV
6.0 kV
8.0 kV
What is absolute the maximum tabulated value of earth fault loop impedance ZS for a 230 V 32A distribution circuit protected by a BS 88-2 Type E device? Mark one answer
0.99 Ω
1.44 Ω
1.69 Ω
1.70 Ω
An obstacle in an electrical installation may be removed?
By any person
Only by skilled persons
Only with the use of a tool or key
Without the use of a tool or key but it shall be secured to prevent unintended removal
Where CA2 conditions exist; in prefabricated hollow walls containing a preinstalled wiring system including accessories, all boxes and enclosures shall have a degree of protection of at least?
IP1X
IP2X
IP3X
IP4X
A single-phase system, has a Connection Type 2 (CT2) surge protection device (SPD) installed. The minimum value of the 'Nominal discharge current' Inspd, for the surge protective device (SPD), between the neutral conductor and the protective conductor is?
10 kA
15 kA
20 kA
5 kA
The ambient temperature of cables shall be considered to be the temperature of the surrounding medium when?
The cables are at maximum operating temperature
The cables are not loaded
The cables are under maximum load
The cables are under minimum load
A label with the wording to meet BS 951 says?
Apprentice's tools - do not remove
Safety electrical connection - do not remove
This installation has wiring colours to two versions of BS7671
Warning - dual supply
Which device is NOT suitable for disconnection whilst carrying current? Mark one answer
A Circuit breaker to BS EN 60898
B Contactor to BS EN 60947-4-1
C Switching device to BS EN 60669-2-1
D Switching device to BS EN 60947-3
Where 'high reliability' is required in a circuit, the use of which of the following should be considered?
Use of IT systems
Use of non RCD TN circuits
Use of safety circuits
Use of unearthed auxiliary circuits
In an electrical circuit when connections are made which of the following types of connection must be available for inspection, testing and maintenance? Mark one answer
A. A compound filled joint
B. A connection between a cold tail and the heating element
C. A connection in an enclosure at a height of 1m above ground level
D. A joint made by welding
When lighting is used in a location where rotating or rapidly moving machine parts are present consideration needs to be given to stroboscopic effects because?
The effects can cause harmonics in the supply cables
The effects can introduce a neutral current in the supply cables
The effects cause moving parts to appear stationary
The effects increase the load on the circuit
Acceptable protective conductors of cross-sectional area 10 mm² or less shall be made of? Mark one answer
Aluminium
Bare steel
Coated steel
Copper
The minimum dimensions for the height of the 'ON' and 'OFF' lettering on a firefighter's switch shall be not less than?
10 mm
15 mm
20 mm
5 mm
Band I and Band II circuits are not normally permitted to be installed in the same wiring system, when this does occur and also when a multicore cable is used, the cores of the Band I and II circuits must be separated by?
A. A cable conduit system with separate compartments
B. A plastic trunking system with metal screened compartments
C. An earthed metal screen of equivalent current-carrying capacity to that of the largest core of the Band II circuit
D. An earthed trunking system with separate compartments
Where it is desired NOT to calculate the sizing of a cpc, we can use the alternative method to Regulation 543.1.3 for sizing a cpc. What is the minimum size cpc to be used when a copper line conductor has a cross-sectional area (c.s.a) of 150 mm² and it is desired to have the cpc also made from copper?
A 35 mm²
B 50 mm²
C 70 mm²
D 95 mm²
When a bus-bar trunking system is installed in a circuit it must comply with?
A BS EN 12954
B BS EN 1648
C BS EN 50086
D BS EN 61439-6
A wiring system is installed in an area where the presence of corrosive substances are present, what is a suitable method of providing additional protection to the wiring system? Mark one answer
Enclose the wiring system in aluminium tape
Enclose the wiring system in copper tape
Enclose the wiring system in plastic tape
Enclose the wiring system in protective tape
Part of your electrical training taught you that whenever you have an interface between conductors you must clearly identify them, such as when making off the line switch return wire for a lighting circuit; but which regulation in BS 7671 states you must do this?
A 510.3
B 512.1.4
C 512.2.4
D 514.1.3
For an IT system, verification of earth fault loop impedance is achieved if the measurement between two live conductors is? Mark one answer
A ≤ 0.8 of the maximum permitted loop impedance
B ≤ 50% of the maximum permitted loop impedance
C ≥ 0.8 of the maximum permitted loop impedance
D ≥ 50% of the maximum permitted loop impedance
What voltage does the test equipment need to inject, to carry out an IR test on a 230-volt household kitchen socket circuit? Mark one answer
A 1000 V
B 230 V
C 250 V
D 500 V
Any insulation arrangement of extraneous-conductive parts intended to satisfy 418.1.4 (iii) shall be able to withstand a test voltage of at least?
1 kV a.c.
2 kV a.c.
3 kV a.c.
4 kV a.c.
An electrical installation certificate shall include?
A section with essential tests
Details of the extent of the work covered by the certificate
The limitations of inspection and testing
The reasons for producing the report
Which of the following is considered to be in a Group 1 medical location? Mark one answer
Anaesthetic room
Intensive care room
Operating theatre
Physiotherapy room
Socket-outlets supplying electrical equipment to be used in the basin of a public swimming pool shall?
Be installed at a height of 3 metres above floor level
Not be permitted
Not be used when the people are in the pool
Only be operated with the use of a tool or key
An electrical contractor is asked to install a new ring final circuit in the horticultural section of a garden centre, the socket-outlets will not exceed 32 amps, and an RCD is to be used to provide ADS for protection against electric shock. What is the maximum permitted rating for this RCD?
100 mA
20 mA
30 mA
500 mA
PME earthing facilities may only be used to provide protective measures on a construction site when all the extraneous-conductive parts are reliably connected?
To the earthing terminal of every distribution board on the site
To the main earthing terminal
To the structural steel work of the new building
Together
On a camping site, TT socket-outlet protective conductors must not be connected to?
A PME earthing facility
B Adjacent pitch protective conductors
C The MET
D The Neutral
Suspension systems for extra-low voltage lighting installations including the supporting conductors, will need to be capable of supporting a mass of no less than?
2 kg
3 kg
4 kg
5 kg
On a marina how many pleasure craft or house-boats may be supplied from one socket-outlet?
1
2
3
4
A floor heating system is installed in a domestic property the heating units shall be connected to the electrical installation via?
Cold tails
Hot tails
Live tails
Warm tails
For PV (Solar Photo-Voltaic) systems, what protective measures are preferred on the d.c. side? Mark one answer
Protection by earth-free local equipotential bonding
Protection by earthing of all live conductors
Protection by electrical connection to earth
Protection by use of Class II insulation
An RCD may be used to provide additional protection to circuits serving a bathroom, the rated residual operating current of the RCD shall be no more than?
100 mA
20 mA
30 mA
500 mA
A 90°C thermosetting cable is operating in the ground where the ambient ground temperature is 15°C. What is the ambient temperature cable correction factor Ca?
1.04
1.05
1.07
1.1
What is the highest rating Type D circuit breaker to BS EN 60898 that will trip in 0.4 seconds when an overcurrent occurs of 640 amps? Mark one answer
20 A
25 A
32 A
40 A
With reference to protected-type non-reversible plugs, socket-outlets, cable couplers and appliance couplers, which standard has been withdrawn?
BS 196:1961
BS 3036:1958
BS 6351
BS 646:1958
A d.c. circuit 25 m in length is installed using two-core 4 mm² 70°C thermoplastic insulated cable. The load draws 10 Amps when using a supply voltage of 245 volts d.c. What will the voltage drop be in the cable?
1.25 volts
2.75 volts
3.25 volts
4.50 volts
